Bosch cdi or alternative?

[mb911]

I am building a nice street engine it is a 2.4 with s pistons and Solex cams with carbs..

I have a Bosch cdi which I am not sure if it works or not and want tp decide to either have it rebuilt or go to something like an msd.

I would really like a rev limiter and have used 6als in the past..

So if you budget 200 for a rebuild or something like an msd what would you choose?

[T77911S]

I have put MSD in 2 of my cars. It's in my 930 now. I like the Rev limiter since I have removed all other electronics.

It probably comes down to do you want the rotor rev limiter or electronic. The electronic on the MSD is of course adjustable

[mb911]

What model did you use..

[tirwin]

Is your Bosch the 3-pin or 6-pin? That might limit your options.

You can buy the MSD Streetfire for ~$120. I am running it in my '83 but I'm not certain about the compatibility with earlier cars. The Streetfire supports both points and magnetic pickup. Why Streetfire vs 6AL? They are very similar. Streetfire should put out plenty of spark, they are both multi-spark but the Streetfire is not repairable. If it goes bad, you throw it in the trash.

The MSD needs braided plug wires and if you're using magnetic pickup you need to reverse the green and violet wires because it operates opposite of the Bosch. You also need to run a dedicated hot wire over from the starter.

By the way, I'm not wed to the MSD. It does the job and is inexpensive. Other brands people have used are Crane and the Classic Retrofit CDI+.

If you want originality, then rebuild the Bosch or go with the CDI+. The CDI+ is not in your budget window though.

[mb911]

My cdi is 3 pin..

There is nothing original about my car so doesn't matter. I did have a 6 al fail once on me.. I never knew they were even repairable.

Street fighter is interesting and they do have rev limiter?

[Trackrash]

Testing my 6 pin CDI

[mb911]

That might be an option for testing..

[Bob Kontak]

Originally Posted by mb911

Street fighter is interesting and they do have rev limiter?

6AL had rev limiting pills you plugged in as you know.

Believe newer versions are more sophisticated yet user friendly wrt rev limitations.

[tirwin]

Streetfire has a rev limiter. There are 2 dials - one for 1000 rpm scale and one for 100rpm scale. Pull the grommet off, set and replace.

[rwest]

Originally Posted by tirwin

Streetfire has a rev limiter. There are 2 dials - one for 1000 rpm scale and one for 100rpm scale. Pull the grommet off, set and replace.

Same for the newer versions of the MSD 6AL

[mb911]

Street fire sounds like a decent place to start. The 6a1 is nice as well but really what is the advantage?

[supdaf]

i recently put a streetfire in my 76. the bosch cdi was working fine. my issue was that a 40 year (and growing) cdi box has a failure in there somewhere. the street fire and coil is inexpensive enough to have a spare in the smugglers box. all the connections plug into the factory plugs so I can replace the msn in 30 min? I can go back to the bosch in a bit more.

works fine up to this point. seems to start a bit better. rev limiting rotor still installed.

[T77911S]

Originally Posted by Trackrash

Testing my 6 pin CDI

i like the old analog MM. I have a few of them but I don't think they all work.


the big cap is probably the big failure item, at least it was on the few I have repaired.
easily checked with a MM but a pain to replace.

[tirwin]

These are probably the most common ways to wire the MSD. I’m not familiar with the 3-pin setup. What are the 3 wires? You’d just need to figure out how to map it to your setup.

I’m assuming you have points so you would use the white wire to trigger spark.

The MSD has 2 power wires. One is the regular 12v. It basically treats this as power for the box but it doesn’t use this wire to generate coil voltage. They want you to run a separate wire (off the starter is fine) with a heavier gauge. This connects to the “heavy” red wire.